AES E-Library

AES E-Library

Hybrid Equalization of Room for Home Theatre System

For home theatre systems, it is necessary to equalize the room impulse responses. It is well known that the perfect inverse filtering over the entire audio frequency range is hard to be met due to the perturbations such as a listener's head movement. For securing larger 'sweet region' we measured at 18 points 3cm at regular intervals horizontally around the both ears position. We synthesize one representative impulse response of these 18 impulse responses in the position-weighted manner using principal component analysis method. We apply this representative impulse response as the target of inverse filtering. For inverse filtering we apply two different methods into two frequency ranges. In the low frequency range we realize a perfect inverse filter using least square method, in the high frequency range we realize linear phase finite impulse response inverse filter using 1/3 octave band frequency magnitude response smoothing. Using this inverse filter we can confirm well-equalized high sound quality in the entire sweet region from the result of experiment.